Sounds like fan is working overly hard because of the ambient temp of your house. Has it always been this loud ?? could be faulty bearings in the fan, or you just havent cleaned the thing since you got it, and leaving it on the floor is probably not helping either, it will suck up alot of dust down there.
Try unplugging it completely and vacuuming all the exhaust ports. Try and do a thorough job as it is probably pretty dusty. My laptop used to overheat (ran at about 60 C) I vacuumed the heat-syncs and it now runs at about 40 C. Big improvement. Good luck!








